1. Technical Field
The present invention relates to a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode, a liquid ejecting head equipped with a piezoelectric element, and a piezoelectric device equipped with a piezoelectric element.
2. Related Art
A liquid ejecting head which ejects liquid droplets from nozzle openings communicating with pressure generation chambers by deforming a piezoelectric element to cause pressure fluctuation in a liquid in the pressure generation chamber is known. As a representative example of this liquid ejecting head, an ink jet type recording head which ejects ink droplets as liquid droplets is used.
An ink jet type recording head, for example, includes a piezoelectric element on one surface side of a flow path formation substrate where pressure generation chambers communicating with nozzle openings are provided, and ejects ink droplets from the nozzle openings by deforming a vibrating plate by driving the piezoelectric element to cause a pressure change in ink in the pressure generation chambers.
Here, the piezoelectric element includes a first electrode, a piezoelectric layer, and a second electrode provided on a substrate. A piezoelectric element using a material obtained by stacking iridium and iridium oxide as a second electrode, or a piezoelectric element which repairs damage when forming a second electrode on a piezoelectric layer by stacking iridium and titanium as a second electrode and performing an annealing treatment has been proposed (see JP-A-10-264384 and JP-A-2014-112646).
However, in a case where a material obtained by stacking iridium and iridium oxide as a second electrode is used as in JP-A-10-264384, damage to a piezoelectric layer when forming iridium oxide may not be repaired. When an annealing treatment is performed in order to repair the damage on the piezoelectric layer, the second electrode may be oxidized and contracted and may have an island shape, and thus, the second electrode may not function as an electrode.
As in JP-A-2014-112646, it is possible to repair damage to the piezoelectric layer by stacking iridium and titanium as a second electrode and performing an annealing treatment, however, electric resistance may increase due to oxidization of titanium, and the strength of an electric field capable of being applied to the piezoelectric layer may decrease.
Such problems are not limited to a piezoelectric element used in a liquid ejecting head of which an ink jet type recording head is representative, and a piezoelectric element used in other piezoelectric devices has the same problems.